Although different forms of psychotherapy have proven effective as treatments for depression, little is known about the mechanisms through which these psychosocial interventions achieve their effects. This competing continuation of R01-MH40472 (previously titled, "What are the Benefits of Interpretive Techniques") requests five years of support for examining the relation between the accuracy of therapists' interventions and measures of attrition, alliance, outcome, and relapse within cognitive (CT) and interpersonal (IPT) treatments for major depressive disorder. Based upon previous studies, our hypothesis is that therapist accuracy during the early phase of treatment predicts retention, the formation of a positive therapeutic alliance, and early symptomatic improvement in both CT and IPT. Therapist accuracy during the later phase of treatment is hypothesized to predict change in social functioning and maintenance of symptom remission for both CT and IPT. Using tapes from the Treatments of Depression Collaborative Research Program (Elkin et al., 1989), three early treatment sessions and three late treatment sessions will be rated for patients' interpersonal themes and for the extent to which therapists address the relevant themes. The Penn Helping Alliance Counting Signs method will be used to assess the therapeutic alliance. Outcome and relapse will be determined from scores on the Beck Depression Inventory, Hamilton Rating Scale for Depression, and the LIFE interview. Data are available on 72 patients for analysis of attrition, 64 for analysis of change in alliance and outcome, and 60 for relapse over 18 months following the acute (16 week) treatment phase. This program of research is designed to advance our understanding of the role of therapist interventions in CT and IPT in inducing change. In addition, this study will contribute to knowledge of the factors that predict outcome and relapse in treatments for depression. Findings from the research can direct revisions to treatment manuals and training programs for therapists, thereby improving treatments for depression.